Calc

Problem

Question asked by jadranka:

L=448m
W=7.5m
H=5cm
I need to calculate the area i m2.
I tried in this way : 448*7.5=3360m2
448*0.05=22.40m2
7.5*0.05=0.38
3360+22.4+0.38=3382.82m2 but my profesor said that`s incotect.
Please help someone!

Follow-up responses...

Problem - Volume To Area

posted by Linn Barringer:

Hello Jadranka.
You seem to be saying that you want the area of a solid.
Think of the 'box' you have described. It's a long thin thing. but it has six sides like a dice, or cube; the top and bottom, the front and back, and the two ends. Drawing it might help.
You then have six "areas" (three pairs of identical areas) that you can work out the area of.

Back and front are both 448m x 5cm.
Top and bottom are both 448m x 7.5m.
Left and right end are both 7.5m x 5cm.

Best to convert them to the same units and, as we want an answer in m2, metres is probably the length unit of choice.

448m = 448m
7.5m = 7.5m
5cm = 0.05m

So the six pieces are now
Back and front are both 448m x 0.05m.
Top and bottom are both 448m x 7.5m.
Left and right end are both 7.5m x 0.05cm.

448 x 0.05 = 22.4
448 x 7.5 = 3360
7.5 x 0.05 = 0.375

There are two of each areas, so we need to double those numbers to
2 x 22.4 = 44.8 m2
2 x 3360 = 6720 m2
2 x 0.375 = 0.75 m2

Add them all together and the total is 6765.55 m2. But I could be wrong - check my logic and my sums!